Cutting planes that pass halfway through an object result in a half section.
The American National Standards Institute (ANSI) recommends using
centerlines for the division line between the sectioned half and the
unsectioned half of a half-section view. Notice that in fact, by using both
centerlines you expose only one quarter of the object.
Use a half-section
view when you must show the interior of one half of the object while
retaining the exterior of the other half. This limits the useful application of
half-section views to symmetrically-shaped objects. Half sections are most
useful when used in assembly drawings. Because half sections require
symmetry and are difficult to dimension, they are not often used in detail
Figure 3-53 shows a half-section view.
Figure 3-53.A half section.
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